Cannot identify the error yylex() produces - flex-lexer

Question

I'm trying to make a .l file for a Pascal-like language. As I'm running it with g++ it crushes after the 20th ish step in the parsing process with different files, one has more definitions in it and one fewer. I tried to get the error but it only send 3 zeros. Did I miss something somewhere?
This is the Utile.h file
#include <map>
#include <iterator>
#include <vector>
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
std::vector<std::string> TS;
typedef struct {
int n;
int elem[20][2];
} FIP;
void addFIP(int code, int posTS, FIP& f){
f.elem[f.n][0]=code;
f.elem[f.n++][1]=posTS;
}
FIP fip;
int pozTS=0;
void printFIP(FIP& f){
ofstream fipFile;
fipFile.open("FIP.txt");
cout<<"nr elem fip"<<f.n<<endl;
for(int i=0;i<f.n;i++)
fipFile<<f.elem[0]<<" "<<f.elem[1]<<endl;
fipFile.close();
}
And this is my specs.l file
%{
#include "Utile.h"
%}
%option noyywrap
%option caseless
LETTER [A-Za-z]
NR_ZEC [0-9]
NR_NZ [1-9]
ZERO [0]
ID {LETTER}({LETTER}|{NR_ZEC})*
NR_BASE10 {NR_NZ}+{NR_ZEC}*|{ZERO}
NR_REAL {NR_BASE10}"."{NR_BASE10}*
DELIMIT [;.,:]
SIR_CAR [\"][^\n]*[\"]
CARACTER "'"[^\n]"'"
ERR_NR_START [0-9]+[a-zA-Z0-9]*
DOT "\."
COLON "\:"
SEMICOLON "\;"
COMMA "\,"
PLUS "\+"
%%
[ \t\n]
[0-9]+[a-zA-Z]+[a-zA-Z0-9]* {printf("Eroare - identificator incepe cu cifra %s \n", yytext);}
read {addFIP(19,-1,fip);printf("%s\n", yytext);}
write {addFIP(20,-1,fip);printf("%s\n", yytext);}
then {addFIP(21,-1,fip);printf("%s\n", yytext);}
variabiles {addFIP(22,-1,fip);printf("%s\n", yytext);}
"=" {addFIP(200,-1,fip);printf("%s\n", yytext);}
\( {addFIP(101,-1,fip);printf("%s\n", yytext);}
\) {addFIP(102,-1,fip);printf("%s\n", yytext);}
\; {addFIP(103,-1,fip);printf("%s\n", yytext);}
\, {addFIP(104,-1,fip);printf("%s\n", yytext);}
\. {addFIP(105,-1,fip);printf("%s\n", yytext);}
\: {addFIP(106,-1,fip);printf("%s\n", yytext);}
"+" {addFIP(300,-1,fip);printf("%s", yytext);}
\- {addFIP(301,-1,fip);printf("%s", yytext);}
integer {addFIP(29,-1,fip);printf("%s", yytext);}
real {addFIP(30,-1,fip);printf("%s", yytext);}
{ID} {addFIP(0,pozTS++,fip);printf("%s\n", yytext);}
{NR_BASE10} {
addFIP(1,pozTS++,fip);
printf("\n%d\n", 1);
}
{NR_REAL} {
addFIP(1,pozTS++,fip);
printf("\n%d\n", 1);
}
"'"[^\n]"'" {
addFIP(1,pozTS++,fip);
printf("\n%d\n", 1);
}
{SIR_CAR} {addFIP(1,pozTS++,fip);printf("\n%d\n", 1);}
. printf("Error %s\n", yytext);
%%
void yyerror (char const *s) {
fprintf (stderr, "%s\n", s);
}
extern FILE *yyin;
main(int argc, char *argv[])
{
yyin= fopen (argv[1] , "r");
yylex();
cout<<yytext;
fclose(yyin);
}
I choose to print the yytext hoping that it will help me figure out where the problem is , but no luck
Also if it help i run it this way
flex specs.l
g++ lex.yy.c
a.exe test.txt

Answer 1

Your FIP structure only has room for 20 entries and addFIP doesn't check to see if it is full before adding a new one. So after about 20 tokens you will start overwriting random memory.
Since you are using C++, why don't you just use a std::vector? You can just emplace_back the tokens, and you don't even need to keep track of how many there are since std::vector takes care of all the bookkeeping.
Having said that, there are very few reasons to create a vector of tokens. Usually you can just process the tokens one at a time.